This interaction module is inspired from the Deep Interactive Inference Network [1]}. Thanks to this explicit interaction modeling, we can later visualize the strength of individual sub-structural interaction pair from the interaction map. To output a probability indicating the likelihood of interaction, we first flatten the \(\mathbf {O}\)  into a vector and use a linear layer parametrized by weight matrix \(\mathbf {W}_\mathrm {o}\)  and bias vector \(\mathbf {b}_\mathrm {o}\) :
\(\mathbf {P} = \sigma ( \mathbf {W}_\mathrm {o} \mathrm {FLATTEN}(\mathbf {O}) + \mathbf {b}_\mathrm {o} ),\) 
